This invention relates to airbags or air restraint systems.
Airbags or air restraint systems, as they are often termed, are a device utilized in passenger vehicles to protect passengers from unintended impacts occurring to the vehicle. The airbags in use are generally a single bag deployed from either the steering mechanism or the instrument panel, and it has been proposed to deploy airbags from the overhead structure, the doors, the seats, or from the side structure adjacent the window.
Airbags are becoming more complex, and currently being considered are dual stage inflators that adjust the inflation pressure of the airbags. Dual stage inflators are especially useful in situations where a small occupant is sitting forward in the seat or when a low speed impact occurs.
The first stage of the inflator is generally sufficient to restrain the occupant during these particular conditions. However, in more severe impacts or with a heavier passenger and with an unbelted occupant in the seating position, the second stage may be activated, thereby increasing the pressure in the airbag to balance the higher energy need for occupant restraint. While these dual level inflator systems are effective, they do involve a complex sensing and deployment algorithm that is specific for each vehicle impact pulse, thus complicating the design and validation process.
It has also been proposed in U.S. Pat. No. 5,927,748, issued Jul. 27, 1999, that a multi-stage inflatable bag might be utilized in air restraint systems. The air restraint system disclosed in the above-mentioned patent has an inner bag which is rapidly inflated to provide an initial cushion and an outer bag which is inflated by gas escaping from the inner bag to provide a secondary cushion for the occupant. The secondary cushion in effect provides a softer spring rate between the occupant and the interior of the car during impact occurrences.
It is an object of the present invention to provide an improved air restraint system having at least two independently deployable airbag cushion volumes incorporated therein.
In one aspect of the present invention, the air restraint system includes a dual depth airbag which has two air chambers. In another aspect of the present invention, the two airbag chambers are individually pressurized during a response to an impact on the vehicle. In yet another aspect of the present invention, one of the airbag chambers deploys nearest or near to the occupant and the other airbag chamber deploys between the first airbag chamber and the interior of the vehicle.
In still another aspect of the present invention, the two airbag chambers share a common bag panel. In yet still another aspect of the present invention, the air bag chambers may have vent openings formed therein. In yet still another aspect of the present invention, the individual airbag chambers have separate opening or neck connections to the vehicle xe2x80x9cAxe2x80x9d pillar.
In a further aspect of the present invention, a control valve is employed within the inflation package to control the selective distribution of inflation gas to one or both of the airbag chambers and to the outside atmosphere. In yet a further aspect of the present invention, the airbag chambers are deployable individually or in concert when required.